Programmed cell death in plant development

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Programmed cell death (PCD) is a genetically-enabled process in which select cells organize their own destruction. PCD is ubiquitous in all eukaryotic kingdoms and is employed by both unicellular and multicellular organisms as part of normal development or in response to external stimuli. In plants, PCD is necessary for growth and survival and can either be developmentally regulated or environmentally induced. A unique example of developmental PCD is perforation (hole) formation in lace plant leaves. These holes are situated equidistantly between longitudinal and transverse veins, giving leaves a lattice-like pattern. During perforation formation, discrete subpopulations of cells undergo PCD while adjacent cells remain intact. Lace plant is native to Madagascar and difficult to grow in aquarium conditions. I have successfully developed a sterile culture system to work on developmental PCD in lace plant. We still do not know what cues trigger PCD at a specific stage of leaf development, so far as the signaling pathways and the molecular mechanisms are concerned. I have characterized the cell death process during perforation formation in lace plant and showed that this aquatic plant is an ideal model system to study developmental PCD in vivo. Therefore, the long term objective of my research is to achieve a fundamental understanding of the mechanisms involved in developmental PCD using lace plant leaf morphogenesis as a model system. This will be achieved through the following objectives: 1. Identification of key regulators and signaling pathways in lace plant PCD. 2. Determination of the role of autophagy during lace plant PCD. 3. Characterization of organelle dynamics during PCD via genetic transformation. 4. Investigation of anthocyanin and other phenolic compounds involved in lace plant PCD. 5. Identification of differentially expressed genes between PCD cells and NPCD cells. These results will help us to determine whether there are common mechanisms between animal and plant PCD or whether they evolved independently.Research in plant PCD has garnered remarkable interest in the past 20 years; however, the signaling pathways, molecular mechanisms, and genes involved in developmentally regulated PCD are still largely unknown. The proposed research will permit my lab group to advance the understanding of various mechanisms involved in plant PCD in a novel way that is unique not only in Canada, but internationally.